System-size dependence of the charged-particle pseudorapidity density at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV for pp, p-Pb, and Pb-Pb collisions

Abstract

We present the first systematic comparison of the charged-particle pseudorapidity densities for three widely different collision systems, pp, p-Pb, and Pb-Pb, at the top energy of the Large Hadron Collider ($\sqrt{s_{\mathrm{NN}}}=5.02$ TeV) measured over a wide pseudorapidity range ($-3.5<\eta <5$), the widest possible among the four experiments at that facility. The systematic uncertainties are minimised since the measurements are recorded by the same experimental apparatus (ALICE). The distributions for p-Pb and Pb-Pb collisions are determined as a function of the centrality of the collisions, while results from pp collisions are reported for inelastic events with at least one charged particle at midrapidity. The charged-particle pseudorapidity densities are, under simple and robust assumptions, transformed to charged-particle rapidity densities. This allows for the calculation and the presentation of the evolution of the width of the rapidity distributions and of a lower bound on the Bjorken energy density, as a function of the number of participants in all three collision systems. We find a decreasing width of the particle production, and roughly a smooth ten fold increase in the energy density, as the system size grows, which is consistent with a gradually higher dense phase of matter.

18 pages, 6 captioned figures, authors from page 13, published version, figures at http://alice-publications.web.cern.ch/node/7846

References in corpus (3)

• Phobos results on charged particle multiplicity and pseudorapidity distributions in Au+Au, Cu+Cu, d+Au, and p+p collisions at ultra-relativistic energies
• Further developments of a multi-phase transport model for relativistic nuclear collisions
• Recent lattice QCD results and phase diagram of strongly interacting matter

Cited by in corpus (6)

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• Collective dynamics in heavy and light-ion collisions -- II) Determining the origin of collective behavior in high-energy collisions
• Role of clustered nuclear geometry in particle production through p-C and p-O collisions at the Large Hadron Collider
• Charged-particle multiplicity distributions over a wide pseudorapidity range in p-Pb collisions at ${\sqrt{\mathbf{s}}}_{\mathrm{NN}}=5.02$ TeV
• Relativistic diffusion model for hadron production in p-Pb collisions at the LHC